1. Field
Example embodiments relate to a complementary metal oxide semiconductor (CMOS) image sensor and method of manufacturing the same, and more particularly, to a CMOS image sensor using a transparent oxide transistor and method of manufacturing the same.
2. Description of the Related Art
Complementary metal oxide semiconductor (CMOS) image sensors are solid state imaging devices which use the CMOS. As in charge coupled device (CCD) image sensors, the CMOS image sensor uses a photodiode. However, a manufacturing process and a method of reading signals of the CMOS image sensor and the CCD image sensor are different to each other. A CMOS image sensor, which has an amplifier in each of a plurality of unit pixels, may be mass produced using a common semiconductor manufacturing device, and thus have a lower manufacturing cost than that of a CCD image sensor.
Also, the size of a CMOS image sensor may be relatively small, and thus a CMOS image sensor has relatively low power consumption. In addition, a CMOS image sensor may be manufactured along with various signal processing devices in one chip. Because a conventional CMOS image sensor has amplifiers allocated to each pixel, noise may be generated in the CMOS image sensor due to a characteristic difference between the amplifiers. However, a signal to noise ratio (SNR) may be relatively high due to various methods of increasing the SNR.
Currently, research is being conducted into a micro process for manufacturing CMOS image sensors. When the size of a chip is reduced by applying the micro process even though the CMOS image sensor has the same number of pixels, more image sensors may be produced from one wafer. As a result, the unit cost of the image sensors may be reduced and productivity of the image sensor increases. Also, the size of a camera module including such image sensors may be reduced and thus, camera phones may be more easily miniaturized.
However, when the size of a unit pixel is reduced due to application of a micro process, realizing a high-quality CMOS image sensor may be difficult. For example, a CMOS image sensor may include a plurality of CMOS transistors and wirings for the CMOS transistors arranged on light receiving areas of the photodiodes.